Mazda Engine LF, L3. Manual - part 9

MECHANICAL 

01–10–19

01–10

4. Insert the piston ring into the cylinder by hand and 

use the piston to push it to the bottom of the ring 
travel.

5. Measure each piston ring end gap with a feeler 

gauge.

• If it exceeds the specification, replace the 

piston, piston pin, piston ring and connecting 
rod as a single unit.

Piston end gap (Standard)

Top: 0.16—0.31 mm {0.0063—0.0122 in}
Second: 0.33—0.48 mm {0.0130—0.0189 in}
Oil (rail): 0.20—0.70 mm {0.0079—0.0275 in}

Piston end gap (Maximum)

1.0 mm {0.0393 in}

End Of Sie

CRANKSHAFT INSPECTION

E5U011011301E01

1. Install the main bearing cap. (See 01–10–28 Main Bearing Cap Assembly Note.)
2. Measure the crankshaft end play.

• If it exceeds the specification, replace the 

thrust bearing or crankshaft so that the 
specified end play is obtained.

Crankshaft end play (Standard)

0.22—0.45 mm {0.0087—0.0177 in}

Crankshaft end play (Maximum)

0.55 mm {0.0216 in}

3. Remove the main bearing cap. (See 01–10–11 

Main Bearing Cap Disassembly Note.)

4. Measure the crankshaft runout.

• If it exceeds the specification, replace the 

crankshaft.

Crankshaft runout (Maximum)

0.05 mm {0.0019 in}

5. Measure the journal diameter in X and Y 

directions at the two points (A and B) as indicated 
in the figure. 

• If it exceeds the specification, replace the 

crankshaft or grind the journal and install the 
undersize bearing.

Main journal bearing size

 STD: 51.980—52.000 mm {2.0464—2.0472 

in}

 US0.25: 51.730—51.750 mm {2.0366—2.0373 

in}

Main journal out of round (Maximum)

0.05 mm {0.0019 in}

Crank pin journal diameter [LF]

 STD: 46.980—47.000 mm {1.8497—1.8503 

in}

 US0.25: 46.730—46.750 mm {1.8398—1.8405 

in}

Crank pin journal diameter [L3]

 STD: 49.980—50.000 mm {1.9677—1.9685 in}
 US0.25: 49.730—49.750 mm {1.9579—1.9586 in}

Crank pin out of round (Maximum)

0.05 mm {0.0019 in}

PISTON RING

B3E0110E082

B3E0110E083

AME2224E311

A

B

X

Y

B3E0110E085

MECHANICAL 

01–10–20

6. Install the main bearing caps and crankshaft.
7. Position a plastigage atop the journals in the axial direction.
8. Install the main bearing caps and cylinder block. (See 01–10–28 Main Bearing Cap Assembly Note.)
9. Remove the main bearing caps. (See 01–10–11 Main Bearing Cap Disassembly Note.)

10. Measure the main journal oil clearance.

• If it exceeds the specification, replace the 

main bearing using the main bearing 
selection table or grind the main journal and 
install the oversize bearings so that the 
specified oil clearance is obtained.

Main journal oil clearance (Standard)

0.019—0.035 mm {0.0007—0.0013 in}

Main journal oil clearance (Maximum)

0.10 mm {0.0039 in}

Main bearing size

STD: 2.506—2.509 mm {0.0987—0.0988 in}
OS0.25: 2.628—2.634 mm {0.1034—0.1037 in}

End Of Sie

CONNECTING ROD INSPECTION

E5U011011211E01

Caution

• The piston and connecting rod cannot be disassembled.

• When replacing the piston, piston pin, piston ring and connecting rod, replace them together as a 

single unit.

1. Install the connecting rod cap. (See 01–10–29 Connecting Rod Cap Assembly Note.)
2. Measure the connecting rod large end side 

clearance. 

• If it exceeds the specification, replace the 

piston, piston pin, piston ring and connecting 
rod as a single unit.

Connecting rod side clearance (Standard)

0.14—0.36 mm {0.0056—0.0141 in}

Connecting rod side clearance (Maximum)

0.435 mm {0.0172 in}

3. Remove the connecting rod cap.
4. Position plastigage atop the journals in the axial 

direction.

5. Install the connecting rod bearing and connecting rod cap. (See 01–10–29 Connecting Rod Cap Assembly 

Note.)

6. Remove the connecting rod cap.
7. Measure the connecting rod oil clearance.

• If it exceeds the specification, replace the 

connecting rod bearing or grind the crank pin 
and use oversize bearings so that the 
specified clearance is obtained.

Connecting rod bearing oil clearance 

(Standard)

0.026—0.052 mm {0.0011—0.0020 in}

Connecting rod bearing oil clearance 

(Maximum)

0.1 mm {0.0039 in}

Connecting rod bearing size [LF]

 STD: 1.498—1.504 mm {0.0589—0.0592 in}
 OS0.25: 1.623—1.629 mm {0.0639—0.0641 in}

Connecting rod bearing size [L3]

 STD: 1.496—1.502 mm {0.0589—0.0591 in}
 OS0.25: 1.621—1.627 mm {0.0639—0.0641 in}

B3E0110E086

B3E0110E087

B3E0110W128

MECHANICAL 

01–10–21

01–10

End Of Sie

BOLT INSPECTION

E5U011010135E01

1. Measure the length of each bolt.

• If it exceeds the specification, replace the bolt.

Bolt length (mm {in})

Cylinder head bolt (With washer)
 Standard: 149.2—149.8 {5.87—5.90}
 Maximum: 150.5 {5.91}
Cylinder head bolt (Without washer)
 Standard: 145.2—145.8 {5.72—5.74}
 Maximum: 146.5 {5.77}
Connecting rod bolt
 Standard: 44.7—45.3 {1.75—1.78}
 Maximum: 46.0 {1.81}
Main bearing cap bolt (Plastic region 

tightening bolt only)

 Standard: 110.0—110.6 {4.33—4.35}
 Maximum: 111.3 {4.38}

End Of Sie

VARIABLE VALVE TIMING ACTUATOR INSPECTION [WITH VARIABLE VALVE TIMING MECHANISM]

E5U011012490E01

Caution

• Variable valve timing actuator cannot be disassembled because it is a precision unit.

1. Confirm that the groove of the rotor and notch of 

the cover at the variable valve timing actuator are 
aligned and fixed.

• If the notch and the bump are not aligned, 

rotate the rotor toward the valve timing retard 
position by hand until they are in place.

• If the rotor and cover are not fixed even 

though their notch and groove are aligned, 
replace the variable valve timing actuator.

End Of Sie

OIL CONTROL VALVE (OCV) INSPECTION [WITH VARIABLE VALVE TIMING MECHANISM]

E5U011014420E01

Coil Resistance Inspection

1. Disconnect the negative battery cable.
2. Disconnect the oil control valve (OCV) connector.
3. Measure the resistance between terminals A and B using an ohmmeter.

• If not as specified, replace the oil control valve (OCV).

Specification

6.9—7.9 ohms [20 

°C {68 °F}]

4. Connect the oil control valve (OCV) connector.

L

B3E0110E088

COVER

NOTCH

ROTOR

B3E0110E089

A

B

B3E0110W151

MECHANICAL 

01–10–22

Spool Valve Operation Inspection

1. Disconnect the negative battery cable.
2. Remove the oil control valve (OCV).
3. Verify that the spool valve in the oil control valve 

(OCV) is in the maximum valve timing retard 
position as indicated in the figure.

• If it exceeds the specification, replace the oil 

control valve (OCV).

4. Verify that the battery is fully charged.

• If it is less than specification, recharge the 

battery.

5. Apply battery positive voltage between the oil 

control valve (OCV) terminals and verify that the 
spool valve operates and moves to the maximum 
valve timing advance position.

• If it exceeds the specification, replace the oil 

control valve (OCV).

Note

• When applying battery positive voltage 

between the oil control valve (OCV) 
terminals, the connection can be either of 
the following:

— Positive battery cable to terminal A, 

negative battery cable to terminal B

— Positive battery cable to terminal B, negative battery cable to terminal A

6. Stop applying battery positive voltage and verify that the spool valve returns to the maximum valve timing retard 

position.

• If it exceed the specification, replace the oil control valve (OCV).

End Of Sie

VALVE CLEARANCE INSPECTION

E5U011012111E03

1. Measure the valve clearance as follows.

(1) Turn the crankshaft clockwise so that the No.1 piston is at TDC of the compression stroke.
(2) Measure the valve clearance at A in the 

figure.

• If the valve clearance exceeds the 

standard, replace the tappet. (See 01–
10–23 VALVE CLEARANCE 
ADJUSTMENT.)

Note

• Make sure to note the measured values for 

choosing the suitable replacement tappets.

Valve clearance [Engine cold]

IN: 0.22—0.28 mm {0.0087—0.0110 in}
EX: 0.27—0.33 mm {0.0106—0.0130 in}

(3) Turn the crankshaft 360

° clockwise so that the No.4 piston is at TDC of the compression stroke.

(4) Measure the valve clearance at B in the figure.

• If the valve clearance exceeds the standard, replace the tappet. (See 01–10–23 VALVE CLEARANCE 

ADJUSTMENT.)

Note

• Make sure to note the measured values for choosing the suitable replacement tappets.

Valve clearance [Engine cold]

IN: 0.22—0.28 mm {0.0087—0.0110 in}
EX: 0.27—0.33 mm {0.0106—0.0130 in}

SPOOL VALVE
(MAXIMUM VALVE TIMING RETARD POSITION

B3E0110E090

VALVE TIMING 
ADVANCE

VALVE TIMING 
RETARD

SPOOL VALVE
(MAXIMUM VALVE TIMING ADVANCE POSITION)

B3E0110E091

A

A

A

A

B

B

B

B

EX

IN

B3E0110E092